Reinforced, thermal insulating, condensation-proof and light admitting member



1959v B. H. BETTCHER 2,918,023

REINFORCED, THERMAL INSULATING, CONDENSATION-PROOF AND LIGHT ADMITTING MEMBER Filed Jan. 27, 1955 2 Sheets-Sheet 1 INVEN TOR. BRUCE H- BETTCHER gram/5Y5 Dec. 22, 1959 B. H. BETTCHER 2,918,023

REINFORCED, THERMAL INSULATING, CONDENSATION-PROOF AND LIGHT ADMITTING MEMBER Filed Jan. 27, 1955 2 Sheets-Sheet 2 III H FIG-5 INVENTOR. BRUCE H. BETTCHER WWW ATTORNEVJ' a (Bruce Bettcher,Poi-tland, Oreg.

Application January. 21, 1955, Serial No. 484,488,

{My present invention comprises am-improvement upon the skylight disclosedand claimed in my copending appli- 'cation, Serial No. 461,066, filed-October 8, 1954.

- f The skylight of the present invention is one which may 'heaeasily fab'ricatedof readily obtainable light transmitzting thermoplastic sheet materialiand easily installed by unskilled workmen, which is thermally insulating, soundproof, .leakproof and condensation-proof. The principal object of the presentinvention is to provide a skylight of theforegoingrcharacter which may be made in large sizes, andyet will withstand extreme temperature and pressure changes. A'further objectof-"the present invention is to make a skylight which may be made in any size, large or small, and which may be evacuated to-a higher degree than possible with the skylight of my previous application, :so as to render the same more effective asan insulator and sound barrier.

A further object of the present invention'is to provide skylights tof the fo'regoing character which may be made of .sheet material .of the same thickness throughout; whereas with the skylight disclosed in my preceding-application it was necessary. to increase the thickness of one or more sheets of theplastic material employed as the dimensions of the skylight were .increased. With the present invention large, economical purchases of a single thickness ofplastic sheet maybe made since all sizes of skylights may be made ofthe rsame 'thickness material.

Further objects'and advantages of the present invention will be more readily apparent from inspection-of the followingspecification taken in connectionwith the accompanying drawings and wherein likenumerals referto like parts throughout.

In the drawings,

. Fig. 1 is a view, in perspective of an'installed skylight construction;

.Fig. 2 is a vertical section taken substantially-along line 2.'.2 of Figs. 1 and 3; a Fig. 3is a transverse section through the-skylightitsclf, taken substantially along line33-of Fig. 2; .Fig. 4 'is a vertical section through a modified form of skylight, taken alonglthe' same plane as Fig. 2-;

Fig. 5 is a partial view of=thesideof abuilding showing the-skylightinstalled as a'window light;

Fig. 6 is a vertical sectiomin somewhat schematic representation, through'apparatus employed in the manufacture of elements of theskylightg-and v I Fig. 7 is a partially broken view, in perspective, of a further modification of the present invention.

The skylight disclosed in Figs. 1, 2 and 3 comprises three rigid, translucent, thermoplastic sheet members 10, 1 1 an'd12, which are'provided with'marginal" areas lying inplanes and adhered to e'a'c'h'dther throughout to form an hermetically sealed, hollow'body. Each of the sheets is corriposed of a'translucent, thermoplastic material, such as methyl-methacrylate, known cornme'reiallyasPlexiglas. Suchsh'e'e't material may be obtai-ned in sheets of standard widtlt aiid length; such as twenty fouririches' by twentyfour inches, and on up to forty-eight" inches by seventy,-

United States Patent O placedon the gasket.

2,918,023 Pitented Dec. 22,

two inches, and in thicknesses of o'ne-eighth inch up to one-quarter of an inch or thicker, and may be clear, .or clouded, either-type being available in various tints. All three sheets employed ina single skylight are preferably of the same thickness, andmay-be-as thin as one-eighth ofv an inch for small skylights, and may be up to threeeighths of an inch, or more, in thickness for large sizes. A feature of my inventio'n is that most skylights, ranging in maximum dimensions from twenty-four inches up to the largest dimension for which standard sheets are available, such as seventy-two inches; may be made-of onequarter inch sheet material. The skylight may be formed to have any convenient.out1ine,.but the preferred forms are square and rectangulan since this eliminates cutting the commercially obtainable sheets, simplifies fabrication of skylight curbs, and eliminates any'necessity for building curved wooden shapes such as would be necessary for installing round, oval or other shapes of skylights.

The outer dome-shaped members 10 and 11 are formed so as to have a plurality of outwardly facing, convex sections, soas to have the maximum rigidity and resistance to crushing when the hollow body is partially vacumized.

Thus, each of the sheets 10 and 11, .for ordinarily encountered skylights, is subdivided along an arched, trans verse, narrow depression indicated at 13 into two sub stantially equal, outwardly co'nvex portions 14. The depressions 13 are preferably flattened along their bottoms and lie parallel to the flat marginalareas whichare sealed together at 15 to form the hollow body. A pair of strips of thermoplastic sheeting are formed into an accordion pleated'truss member indicated M16, and the o'pposite bends thereof are cemented to the inner surfaces ofthe depressions 13 andto the opposed surfaces of the intermediate sheet 12 to form a double truss extending across the interior of the hollow body, the arches of the truss being the botto'ms'of the depressions 13, and the central chord comprising the sheet 12. a The truss is of suflicient strength so as to be indesructible and unyielding under pressures of the highest order which might be encountered. Therefore, the unsupportedspans of the sheets 10 and 11 subjectedv to loading under differences between internal and external pressures are reduced from the entire width of the skylight to half the width of the skylight.- The unit loading on askylight of this character may be far more than double the unit loading which a single span skylight will endure. The intermediate sheet 12 is preferably provided with openings 17 therethrough so that pressures throughout the interior will be equalized.

It will readily be appreciated that the overall thickness of a skylight formed in accordance with my presentinvention in its preferred form is less than would be the case if the central depressions were not provided, and the strength thereof is materially increased over the strength of an untrussed skylight made of considerably thicker material. However, the insulating value is still greatest and sufiicient toward the center ofthe skylight where the greater need for insulation exists.

The skylight is illustrated as being applied to a skylight curb 20 surrounding a light well in the roof of a building. The curb 20 has its rim lying in a single plane and is quickly and easily constructed as a rectangle of wooden beams surrounding a square opening in the roof decking 21. Any suitable weatherproofing material may be employed on the roof, such as the roof felt 22 to which asphalt and gravel is applied, as indicated at 23. The roofing felt should extend up to the top of the curb, preferably passing over a coping strip 24; and the upper, outer edge of the curbis preferably chamfered, as indicated at 26. A gasket 27 of moistureproof material such as neoprene-bound cork, is laid on the rim of the curb and, preferably, adhered thereto, and the skylight is then A plurality. of retaining rails 28,"

each Comprising an angle bar of lightweight, stainless steel or other noncorrosive alloy, and having a long, vertical flange 29 and a relatively short, horizontal flange 30, are fixed to the curb in a manner to retain the skylight. The upper flange 30 overlies the margin of 'the skylight, and the vertical flange 29 extends alongside of and in outwardly spaced relation to the outer edge of the skylight and the outer surface of the curb. The re-' taining rail is preferably maintained in position by suitable means such as twist nails 31 which pass through neoprene washers 32 to space the rail from the curb and provide a drain passage therebetween. The retaining rail is provided in linear sections, the ends of which may be mitered to form neat joints, or merely overlapped as desired. The meeting edges of the sections of retaining rail may be suitably fastened together to providea stronger structure, but it is not required that the space between the retaining rail and the skylight be sealed against moisture. Any water which runs beneath the flange 30 will drip from the edge of the skylight and fall through the space between the retaining rail and the curb. Preferably, the lower sheet 11 is provided with a downwardly turned, angular drip flange 33 to further insure against water running back between the skylight and the curb.

he drain passage is quite narrow, so that there is not much tendency for wind to blow water back between the drip flange and the roofing felt, and if any is blown 'back it will be blocked by the gasket 27. It is empha sized that the retaining rail is merely a retainer, as distinguished from expensively installed flashing or other weatherproofing means. The interior of the light well may be smooth, since there are no expensive interior gutters or drain tubes leading to the outside of the curb. Therefore, the interior surfacing such as plaster, indicated at 34, may be easily applied.

A modification of the skylight is illustrated in Fig. 4, in which it is seen that three sheets 10, 11 and 12 exactly as previously described, are formed with convexities 14 and intervening depressions as at 13, and interior truss members are provided, in this case in the form of a pair of flat sheets of thermoplastic material indicated at 35, the edges of which are respectively cemented to the sheets 10, 11 and 12. Preferably, such sheets are provided with openings 36 so as to lighten the construction as much as possible and permit free flow of air throughout the entire construction.

A further modification is illustrated in Fig. 7, in which the outer sheets 40 and 41, the latter being provided with a drip flange 43 as previously described, are cemented at their edges to an intermediate plain sheet 44. In this instance each of the outer sheets 40 and 41 are subdivided into four substantially equal, convex portions 45 separated from each other by depressed, transverse areas indicated at 46, in the form of a cross. A plurality of internal truss members 48 are cemented in position between the intermediate sheet and the depressed areas as previously described, so as to subdivide the hollow body into four spans instead of one large span. The number of subdivisions may be as desired, and the skylight may comprise several spans along the length of a long, rectangular skylight. The form of trussing may vary, as previously described. As previously described, the intermediate sheet 44 is provided with a plurality of openings 49 to equalize pressures and permit air to flow throughout the construction.

The versatility of the present invention is illustrated in Fig. wherein it is seen that a'plurality of small skylights 50 constructed in accordance with the present invention may be retained in a frame, such as a window frame 51, which is mounted in an opening in the wall 52 of a building. Such a construction is of particular utility in bathroom windows, where light but not visibility is desired, or in factory buildings, or in other installations where glass brick is now employed. The term skylight" as used herein is meant to include such constructions.

The skylight thus formed is a pillow-shaped, air impervious construction, subdivided into stress areas of lesser extent than the entire surface area thereof, and providing a soundproof, thermally insulated, and condensation-proof construction. Tests have demonstrated that whereas a single wall skylight may have moisture condensed on its inner surface when the outside temperature is below forty degrees Fahrenheit and the inside relative humidity is within normally encountered ranges, the present construction will prevent condensation if the temperature drops below zero degrees Fahrenheit, unless the inside relative humidity should be far in excess of normal conditions, and even under abnormal conditions condensation is slight. The interior of the pillow-shaped body is preferably maintained under partial vacuum. The thermal insulating qualities of a vacuumized space are well known, it being suflicient to state that thermal c0nductivity through a single walled skylight is substantially four times that through a skylight formed in accordance with the present invention and vacuumized to six or seven inches of mercury, at sea level. Sound transmission through the present invention is correspondingly reduced. The improved subdivided skylight disclosed in the present application may be vacuumized to a much higher degree, which has been found desirable in certain localities. For example, some cities in the United States are situated above four thousand feet, and as such are subjected to extreme changes in temperature and atmospheric pressure. Under such conditions implosion may occur if the extent of vacuumizing is excessive or explosion may occur if the body has not been vacuumized enough. Furthermore, thermal insulating value may be lost, particularly when the air temperature is excessively low and the sun is shining directly on the skylight. By etfectively subdividing the skylight into small stress areas, the skylights may be vacuumized to have six to eight inches of mercury vacuum pressure at average conditions at high elevations.

The outer sheets of the skylight are formed as described in my application identified above, by slightly modified apparatus. The flat sheet of thermoplastic material is heated to a floatable condition, and is then clamped to a table 60 having a felt covering 61 thereon, by means of a rectangular angle bar frame 62 and C-clamps 63. Air under pressure, supplied from a suitable source such as the pump 64, is admitted through the center of the table 'by means of a pipe 65 under control of a valve 66, so as to blow the sheet into a dome shape. In this instance the frame 62 is provided with a crossbar 67 which holds the center transverse portion of the sheet to the shape desired for the depressed area 13, and pressure is continued until the convex areas 14 are provided. The air and table may be maintained in heated condition, such as by means of the resistance heater 68 connected to a source of current 69 and controlled by a switch 70. It is to be appreciated that the frame may be provided with transverse bars 67 to provide the number of depressed areas required, and that they may be crossed in order to form a skylight such as illustrated in Fig. 7.

When forming sklights embodying trusses such as the pleated strips 16, the strips are formed to shape by heating and bending. A suitable adhesive is applied to the contacting bends of the strip 16 and it is fitted into place in the outer sheet. Adhesive is applied to the marginal areas and bends of a pair of such subassemblies and the two are then clamped to the central sheet. The same procedure is. followed when using internal struts such as illustrated in Fig. 4. As illustrated and described in the above-identified copending application, air is blown through the interior and around the exterior of the skylight until all solvent is evaporated, annealing of the sheets is effected, then the vacuum is drawn and plugs applied to the openings through which air was circulated and the vacuum drawn.

Having illustrated and described a preferred embodiment of the present invention, it should be apparent that the same permits of modification in arrangement and detail. I claim as my invention all such modifications as come within the true spirit and scope of the appended claims.

I claim:

1. A skylight comprising a central, flat sheet of light transmitting material, two dome-shaped members of air impervious, light transmitting sheet material placed on opposite sides of said central sheet to form a pillowshaped skylight subdivided transversely across the interior thereof by said flat sheet, said dome-shaped sheets each having a continuous, flat margin hermetically sealed to the marginal portions of the adjacent surfaces of said central sheet throughout their extent, and light transmitting truss members secured respectively to the opposite surfaces of said central sheet and to the inner surfaces of said dome-shaped members, said truss members being in alignment with each other and subdividing said skylight into stress areas of less extent than the exent of the skylight, the interior of said skylight being under partial vacuum, and said central sheet having an opening therethrough for equalization of pressures on opposite sides thereof.

2. A skylight comprising a pair of substantially identical, dome-shaped, light transmitting sheet members disposed in opposed reverse relation to each other to form a pillow-shaped, hollow skylight, a flat sheet subdividing the interior of said skylight with the edges of said members and said fiat sheet being hermetically sealed to each other throughout whereby said skylight may be placed under vacuum, said flat sheet having an opening therethrough for equalization of pressures on opposite sides thereof, and light transmitting truss members secured respectively to the opposite surfaces of said flat sheet and to the overlying inner surfaces of said dome-shaped members to form therewith a double truss extending across the interior of the skylight, said dome-shaped members each being subdivided into smaller, outwardly convex sections by arched depressions extending across the extent of the skylight, and said truss members each being secured to said dome-shaped members along the bottoms of said depressions.

References Cited in the file of this patent UNITED STATES PATENTS 1,370,974 Kirlin Mar. 8, 1921 1,495,948 Carney May 27, 1924 2,004,894 Hughes June 11, 1935 2,384,157 Burke Sept. 4, 1945 2,610,593 Wasserman Sept. 6, 1952 2,624,978 Hohmann Jan. 13, 1953 2,638,187 Tate May 12, 1953 2,710,335 Wong June 7, 1955 FOREIGN PATENTS 229,450 Great Britain Feb. 26, 1925 947,077 France Jan. 3, 1949 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,918,923 December 22, 1959 Bruce II, Bettcher It is herebjr certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 22, for "vacumized" read vacumnized line 38, for "indesructible" read indestructible g column 4, line 42, for "iloatvable" ilowable' day of 1960.0

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Officer Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION December 22, 1959 Patent No, 2,918,023

Bruce R. Bettcher' It is hereby certified that error appears in the -printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

for "vacumized" read we veeuwnized line 38,

Column 2, line 22,

column 4, line 42, for

for inde-s'mlctible read indestructible "iloetahle" ilowable' '0 Signed and sealed this 31st day of 1960.0

(SEAL) Attest:

KARL H. .AJEINE ROBERT C. WATSON Commissioner of Patents Attesting Officer 

